Add note about TF_PLUGIN_CACHE_DIR

[wiktorn]

I noticed that tests on my laptop worked very slow, especially compared to GitHub workflows or my workstation.

For example, on my laptop (connected through medium bandwidth, high latency 3G connection) speedup is 26x :

pytest tests/blueprints
=============================== 41 passed, 1 warning in 4182.25s (1:09:42) ===============================

vs:

TF_PLUGIN_CACHE_DIR=/tmp/tfcache pytest tests/blueprints
=============================== 41 passed, 1 warning in 159.37s (0:02:39) ===============================

On my workstation, the speed up is not so drastic, but stil significant (1.58x faster):

/usr/bin/time  pytest tests/blueprints
=============================== 41 passed, 1 warning in 315.45s (0:05:15) ===============================
324.84user 75.50system 5:15.75elapsed 126%CPU (0avgtext+0avgdata 153676maxresident)k
0inputs+15606560outputs (17major+1854428minor)pagefaults 0swaps

vs:

TF_PLUGIN_CACHE_DIR=/tmp/tfcache /usr/bin/time pytest tests/blueprints/
=============================== 41 passed, 1 warning in 199.81s (0:03:19) ===============================
270.63user 37.29system 3:20.12elapsed 153%CPU (0avgtext+0avgdata 153336maxresident)k
0inputs+493496outputs (5major+1822243minor)pagefaults 0swaps

I think it is at least worth mentioning in the documentation or implementation in conftest.py. Any ideas which directory would be the best to use for this purpose?

[juliocc]

Thanks @wiktorn. Nice addition to the contributing guide.

FWIW I have this in my terraformrc

plugin_cache_dir = "$HOME/.terraform.d/plugin-cache"

[ludoo]

Thanks @wiktorn. Nice addition to the contributing guide.

FWIW I have this in my terraformrc

plugin_cache_dir = "$HOME/.terraform.d/plugin-cache"

same here :)